Process and apparatus for manufacturing copper-plated steel wire

ABSTRACT

Drawing grease is applied to continuously advancing steel wire rod, which is subsequently drawn in succession through a plurality of drawing dies to form wire, which is continuously advanced along a predetermined path. Electric current is passed through the advancing wire along a predetermined portion of the path to heat and anneal the wire. The advancing wire, which has been annealed, is pickled in an electrolytic bath and is subsequently rinsed and thereafter subjected to a chemical copper-plating treatment in a bath consisting mainly of copper sulfate solution. Drawing grease is applied to the advancing copper-plated wire, which is subsequently drawn through at least one drawing die. The advancing wire which has been drawn is finally wound on spools.

United States Patent PROCESS AND APPARATUS FOR MANUFACTURING COPPER-PLATED STEEL WIRE 10 Claims, 3 Drawing Figs.

US. Cl 72/47, 72/41, 72/286 Int. Cl ..B2lb 45/00, B2 1c 9/00 Field of Search 72/41, 286, 47; 205/21 Primary Examiner-Charles W. Lanham Assistant ExaminerMichael .1. Keenan Att0rney-Holman & Stern ABSTRACT: Drawing grease is applied to continuously advancing steel wire rod, which is subsequently drawn in succession through a plurality of drawing dies to form wire, which is continuously advanced along a predetermined path. Electric current is passed through the advancing wire along a predetermined portion of the path to heat and anneal the wire. The advancing wire, which has been annealed, is pickled in an electrolytic bath and is subsequently rinsed and thereafter subjected to a chemical copper-plating treatment in a bath consisting mainly of copper sulfate solution. Drawing grease is applied to the advancing copper-plated wire, which is subsequently drawn through at least one drawing die. The advancing wire which has been drawn is finally wound on spools.

PATENIE0nEc28|9n 31630.05?

SHEET 1 OF 3 L' LL Inventor:

PATENTEDBEBZMTI 31630.05? SHEET 2 OF 3 FIG-2 FI G. 5

Inventor H. JY'KafimE/Ei.

B7 WW PROCESS AND APPARATUS FOR MANUFACTURING COPPER-PLATED STEEL WIRE This invention relates to a process of manufacturing copperplated steel wire, which is particularly intended for use in CO gas-shielded welding operations, and a plant for carrying out the process.

Copper-plated wire is generally manufactured in a process in which steel wire rod is predrawn in high-speed predrawing units and by means of upcoilers is wound up on reels holding up to about 1,000 kilograms of wire. The reels are then placed into furnaces, preferably pot furnaces, and the wire on the reels is annealed in the furnaces under atmospheric pressure to eliminate the effect of the work hardening of the wire. The lengths of reeled wire are then combined in a set containing a relatively large number of wires, e.g., 46 wires, which are withdrawn from the reels and move parallel to each other through the units which will be listed hereinafter. The wires move first through an electrolytic or purely chemical pickling bath and are then rinsed, are copper-plated by immersion in a bath, and a drawing grease, such as soap or oil is applied thereto. The wire is then reduced to the desired diameter by an immersion-drawing device. Thereafter, the wires are wound up on spools with the aid of an upcoiler, which is preferably driven by a repulsion motor. The above-mentioned large number (e.g., 46) of wires must move in parallel to each other through the above-mentioned units of the plant to ensure a satisfactory output because the wires can move only at relatively low speeds through the pickling and immersion baths. For this reason, the production costs of such plant are extremely high.

It is an object of the invention to avoid the above-mentioned disadvantages and to continuously manufacture copper-plated wire from a single strand of wire rod at a high speed and without intermediate storage. In a process of the kind described first hereinabove, this object is accomplished in that steel wire rod which is continuously advanced has drawing grease applied to it in known manner, is then drawn through a plurality of drawing dies, electric current is passed through the wire in known manner so that the wire is highly heated and annealed, the wire is pickled in an electrolytic bath, which contains preferably sulfuric acid, and is subsequently rinsed, mainly with water sprayed in the wire, thereafter is subjected to an electroless chemical copper-plating treatment in a bath consisting mainly of a copper sulfate solution, and the resulting plated wire has drawing grease applied to it and is drawn through one or more drawing'dies and is finally wound up on spools.

One of the various plants which are suitable to carry out the process according to the invention is characterized in that a known multidrurri predrawing device is provided, which comprises a plurality of drawing dies, e.g., five drawing dies, each of which is preceded by a vessel which is adapted to hold drawing grease and which is passed through by the wire to be copper-plated. An annealing device is provided which contains two contact baths which are electrically insulated from each other and in known manner contain an electrically conducting liquid. These contact baths are connected to respective poles of a source of current, preferably a DC source, the wire enters the first contact bath, then the second contact bath and then again the first contact bath. A container is provided for an electrolytic pickling bath, which preferably contains sulfuric acid. A spraying device for rinsing the wire is provided and a container for a bath consisting mainly of a copper sulfate solution. A drawing unit, which is preferably continuously adjustable and comprises a vessel which is adapted with drawing grease and which is passed through by the wire, a drawing die, and succeeded by an upcoiler are provided. It has proved suitable to provide a roller which is disposed between the annealing unit and the pickling bath and which is wrapped by a plurality of turns of the wire so that the cooling of the wire is delayed.

The present process will now be explained more fully with reference to an embodiment of the plant according to the invention, which embodiment is diagrammatically shown in top plan views on the accompanying drawings marked FIGS. I to 3.

Coils of steel wire rod 16 are placed by means of a slewing crane 1 onto a reversible or double reel 3, in which the ends of adjacent coils are joined by known wire butt-welding machine 2 so that the wire rod 16 forms a substantially endless strand. The wire rod 16 then moves through a loop remover 4 and through a wire-bending and descaling machine 5, in which the wire is strongly bent by means of a plurality of rotatable rolls so that the scale flakes off and the wire is descaled. Turning to FIG. 2, the wire rod 16 is then pulled in succession through the five drawing dies of the predrawing unit 6, which comprises five drums. Each drawing die is preceded by a vessel, which is filled with drawing grease and the wire 16 passes therethrough. The wire I6 then enters the annealing device 8, which comprises two electrically insulated lead baths (contact baths) 8 and 8". These lead baths 8' and 8" are connected to respective poles of a direct-current source, which may consist, e.g., of a motor-generator set. The tank for the first lead bath 8' is grounded. With the aid of rollers, the wire 16 is passed into the first lead bath 8', then into the second lead bath 8" and thereafter back into the first lead bath 8'. The free length i of wire 16 between the two lead baths 8 and 8" is much longer on the returning side than on the advancing side. This is accomplished in a simple manner in that the rollers serving to deflect the wire 16 are disposed on different levels. In spite of the high speed of the wire 16, only a very short length of the wire is subjected to annealing because the heat required for annealing is produced in the wire 16 itself by the electric current flowing through the wire. All annealing processes in which external heat is applied to the wire require the same to be subjected to annealing in an additionally long length. The annealed wire moves in a plurality of turns around a roller 8" so that the cooling of the wire is delayed. When the wire 16 has a temperature of about 200 C., it is passed also with the aid of rollers into the electrolytic pickling bath 9. The source of current for the electrolytic pickling operation consists of a transformer, which is provided with a full-wave rectifier. The wire 16 is connected to the positive pole of the source by a plurality of contact rollers, which are disposed outside by the electrolytic bath liquid. The negative pole of the source of current is connected to a tubular cathode, which is disposed in the electrolyte and is traversed by cooling water. The electrolyte may consist, e.g., of sulfuric acid having a concentration of about 12 percent. The pickling bath 9 is covered and provided with a suction device. The wire 16 passes through the tank holding the pickling bath 9 twice in mutually opposite directions and in then rinsed outside the pickling bath 9 by a spraying device, in which water is sprayed onto the wire 16 so that the sludge which has deposited on the wire 16 in the pickling bath is removed.

The spraying device is succeeded by a continuously variable capstan drive 10, which continuously advances the wire 16 through the annealing unit 8 and the pickling bath 9. The wire 16 which leaves from the capstan drive 10 is virtually under no tension and is then passed with the aid of rollers through the copper-plating bath 11, which consists mainly of a copper sulfate solution and in which the wire is subjected to an chemical copper-plating treatment. During this treatment, the wire 16 passes several times in mutually opposite directions through the tank of the copper plating bath II. This tank is lined with plastics material to prevent an undesired formation of a cell. A plurality of immersion heaters are installed in the tank and are controlled with the aid of thermostats to maintain the bath temperature at an adjusted value. The wire 16 from he copper-plating bath 11 then passes through a vessel which is filled with drawing grease so that a grease layer is applied to the wire, and through the drawing die of a drawing unit I2, which has a speed of operation that is variable. As a result of this operation, the wire 16 has a uniform diameter and a smooth periphery. In a known immersion-drawing machine 13, (FIG. 3) the wire 16 is then reduced to the desired final size with the aid of drawing dies in up to thirteen drawing passes. With the aid of a known upcoiler 14 the wire 16 is then wound up onto spools 14'. A plurality of switches are provided between the five-drum predrawing device 6 and the upcoiler 14 comprising rollers, which are spring-urged against the passing wire 16. These switches automatically stop all parts of the plant immediately in case of trouble, e.g., in case of breakage of the wire 16. This automatic-switching system can be overridden by an additional switch.

All indicating devices and all switches which are required for the operation of the plant are combined on a central control desk 15 (FIG. 2) so that the plant can be controlled by a single operator, who can control even a plurality of such plants substantially at the same time. The plant also comprises a pointing rolling mill 7, by which the wire end to be threaded through the drawing dies at the beginning of the operation can be reduced to the required diameter.

Different from the processes previously employed to make copper-plated wires for use in CO gas-shielded welding operations, the process according to the invention enables an almost fully automatic manufacture of such wires. The work required at the beginning of the operation to thread the wire through the drawing dies and the others parts of the plant is much less in the plants serving to carry out the process according to the invention that in known plants because only a single strand of wire is used in the process according to the invention. Further advantages of the process according to the invention reside in that the capital cost and the space requirement of the plants serving to carry out the process are much smaller than with the previously known plants for copper-plating steel wire. As a result, the process according to the invention greatly reduces the costs of manufacturing copper-plated steel wire. The copper layers applied by the process according to the invention are very firmly bonded to the base material because in the process according to the invention the steps of annealing, pickling and copper-plating the wire are carried out in close proximity in a continuous operation without an intermediate storage of the wire.

What is claimed is:

l. A process of continuously and automatically manufacturing copper-plated steel wire, which comprises the steps of:

providing and continuously advancing steel wire rod;

applying drawing grease to said advancing steel wire rod;

predrawing said advancing greased steel wire rod;

continuously advancing said wire along a predetermined path;

passing electric current through said advancing wire along a predetermined portion of said path to heat and anneal said wire;

wrapping said advancing wire onto a roller to delay the cooling of said wire;

pickling said advancing wire, which has been annealed, in

an electrolytic bath containing sulfuric acid;

rinsing said advancing pickled wire;

chemically copper-plating said advancing rinsed wire in a bath substantially consisting of copper sulfate solution; applying drawing grease to said advancing plated wire; drawing said advancing greased wire; and

finally winding said drawn wire up onto spools.

2. A plant for continuously and automatically manufacturing copper-plated steel wire, which comprises:

a multidrum predrawing device for drawing wire rod to form wire, said predrawing device comprising a plurality of predrawing dies and a plurality of drawing grease vessels, each of which precedes one of said drawing dies and hold drawing grease;

an annealing device, which comprises first and second contact means, which include electrically conducting liquid, each means being electrically insulated from the other;

a source of electric current having two poles, each of .which is connected to one of said contact means;

an electrolytic pickling bath containing sulfuric acid;

a spraying device for rinsing the wire with water;

a container adapted to hold a chemical copper-plating bath consisting mainly of a copper sulfate solution; a drawing unit which comprises a vessel adapted to hold drawing grease, and a drawing die;

means for moving the wire in succession through said above-mentioned elements;

an upcoiler for coiling the finished wire; and

a roller disposed between said annealing device and said pickling bath and adapted to be wrapped by a plurality of turns of said wire to delay the cooling of said wire.

3. A plant as claimed in claim 2, in which predrawing device comprises five predrawing dies.

4. A plant as claimed in claim 2, in which said electrically conducting liquid consists of molten lead.

5. A plant as claimed in claim 2, in which said source of current is a source of direct current.

6. A plant as claimed in claim 2, in which said means for drawing said wire in succession through said above-mentioned elements is operable at variable speed.

7. A plant as claimed in claim 2, which further comprises:

a reel carrier which is adapted to carry two reels, each of which is adapted to hold a coil or wire rod;

said reel carrier being rotatable through to selectively place one of said reels in a supplying position and the other in a receiving position;

a wire butt-welding machine operable to join adjacent ends of wire coils carried by said reels;

means for continuously supplying said wire from said one reel to said predrawing device; and

a loop-remover for removing loops from said wire as it is supplied from said one reel to said predrawing device.

8. A plant as claimed in claim 2, wherein said annealing device comprises:

said contact means are liquid contact baths;

means for guiding said wire along a forward path from said first contact bath to said second contact bath; and

means for guiding said wire along a return path from said second contact bath to said first contact bath;

said return path being much longer than said forward path.

9. A plant as claimed in claim 2, in which said means for moving said wire comprises a continuously variable capstan drive arranged between said electrolytic pickling bath and said copper-plating bath.

10. A plant as claimed in claim 2, which further comprises an immersion-drawing machine arranged between said drawing unit and said upcoiler, said immersion-drawing machine having a plurality of drawing dies. 

2. A plant for continuously and automatically manufacturing copper-plated steel wire, which comprises: a multidrum predrawing device for drawing wire rod to form wire, said predrawing device comprising a plurality of predrawing dies and a plurality of drawing grease vessels, each of which precedes one of said drawing dies and hold drawing grease; an annealing device, which comprises first and second contact means, which include electrically conducting liquid, each means being electrically insulated from the other; a source of electric current having two poles, each of which is connected to one of said contact means; an electrolytic pickling bath containing sulfuric acid; a spraying device for rinsing the wire with water; a container adapted to hold a chemical copper-plating bath consisting mainly of a copper sulfate solution; a drawing unit which comprises a vessel adapted to hold drawing grease, and a drawing die; means for moving the wire in succession through said above-mentioned elements; an upcoiler for coiling the finished wire; and a roller disposed between said annealing device and said pickling bath and adapted to be wrapped by a plurality of turns of said wire to delay the cooling of said wire.
 3. A plant as claimed in claim 2, in which predrawing device comprises five predrawing dies.
 4. A plant as claimed in claim 2, in which said electrically conducting liquid consists of molten lead.
 5. A plant as claimed in claim 2, in which said source of current is a source of direct current.
 6. A plant as claimed in claim 2, in which said means for drawing said wire in succession through said above-mentioned elements is operable at variable speed.
 7. A plant as claimed in claim 2, which further comprises: a reel carrier which is adapted to carry two reels, each of which is adapted to hold a coil or wire rod; said reel carrier being rotatable through 180* to selectively place one of said reels in a supplying position and the other in a receiving position; a wire butt-welding machine operable to join adjacent ends of wire coils carried by said reels; means for continuously supplying said wire from said one reel to said predrawing device; and a loop-remover for removing loops from said wire as it is supplied from said one reel to said predrawing device.
 8. A plant as claimed in claim 2, wherein said annealing device comprises: said contact means are liquid contact baths; means for guiding said wire along a forward path from said first contact bath to said second contact bath; and means for guiding said wire along a Return path from said second contact bath to said first contact bath; said return path being much longer than said forward path.
 9. A plant as claimed in claim 2, in which said means for moving said wire comprises a continuously variable capstan drive arranged between said electrolytic pickling bath and said copper-plating bath.
 10. A plant as claimed in claim 2, which further comprises an immersion-drawing machine arranged between said drawing unit and said upcoiler, said immersion-drawing machine having a plurality of drawing dies. 